Plant Parasites of Europe

leafminers, galls and fungi

gallers on Chaerophyllum

Dichotomous table for gallers on Chaerophyllum

by Hans Roskam

1a On parts of inflorescence or fruits => 15

1b On stems or leaves => 2

2a Bulge-shaped, usually yellowish coloured or margined galls on leaves or stems, soon bearing fruiting bodies of rust fungi on their surface => 10

2b Malformations caused by animal parasites or by fungi, fruiting inside the gal => 3

3a Malformations on leaves caused by aphids => 7

3b Malformations caused by different parasites => 4

4a Leaves variously folded, curled or distorted => 5

4b ulge-like, depending on the infected plant part, variously large, compact, pale-green swellings on leaf veins, -midrib, or shoot axis, exceptionally even on young fruits. Containing fungus spores inside. Ch. hirsutum, villarsii: Protomyces macrosporus

5a Leaves disfigured on leaf blades and midrib => 6

5b Development of leaves completely stunted; midrib normal; only the leaf blade folded upward, ± curled and thickened close to midrib. Containing several white larvae. Ch. aromaticum, hirsutum: Macrolabis heraclei

6a Main- and side axis ± stunted, the ± developed leaves deflected, with their ± curled leaf blades loosely converging, nest-like. Leaf blades close to infestation deep-green. Chaerophyllum spp.: Philaenus spumarius

6b Mainly apical parts of leaves stunted and distorted, leaf blades locally swollen, curled. Malformation stunted, often inconspicuously converging, nest-like. Ch. temulum: Trioza apicalis

7a Aphids green => 8

7b Aphids black. Leaflets curled and converging; upper stem leaves slightly bleached. Ch. bulbosum: Aphis fabae

8a Aphids yellowish-green to green, siphunculi of same colour, long, slightly swollen => 9

8b Aphid greenish, siphunculi black, long, swollen. Ch. aromaticum, hirsutum, temulum: Hyadaphis foeniculi

9a Aphid with a “double” cauda; antennae not reaching the middle of body. Leaves curved and curled; the inflorescence is often simultaneously infected and distorted. Ch. temulum: Cavariella pastinacae

9b Cauda simple, antennae longer than half the body length; leaves curled, sometimes reddened at margin; usually only slightly curled. Ch. hirsutum: Myzus persicae

10a Bulges on leaves and stems caused by a fungus, developing aecia => 12

10b Fungus develops only telia; leaf axis and stem, also stalk of umbel, with 1–2 mm long pads, which often coalesce to ± conspicuous and curved, bulging swellings => 11

10c Leaves blistered, especially when young, with whitish down on underside. Ch. aromaticum, aureum, bulbosum, temulum: Plasmopara chaerophylli

11a On Ch. bulbosum and villarsii: Puccinia enormis

11b On Ch. hirsutum: Puccinia pozzii

12a Aecia on Ch. aromaticum or bulbosum, rarely aureum => 14

12b Aecia on Ch. aureum, hirsutum, temulum => 13

13a On Ch. hirsutum. Fungus develops on swollen, orange-red pads, only spermogonia and deeply countersunk, not protruding, pustule-shaped aecia: Puccinia bistortae

13b Aecia pustule-shaped, with rather weakly developed, loose peridium, with outer wall not, or weakly thickened. Chaerophyllum spp.: Puccinia chaerophylli

14a Aecia in dense groups, on leaf underside on arched spots or often in long pads on veins, midrib, stalks or on stems. Peridium weakly developed, loose, opening with an oblong slit. Ch. aromaticum: Puccinia aromatica

14b Aecia pustule-shaped, caeoma-like, opening with oblong slit, cells of peridium similar to spores. Ch. aureum, bulbosum, coloratum, hirsutum, temulum: Puccinia retifera

15a On fruits => 16

15b Centre of stalk of (partial) umbel ± swollen club-shaped or globular. Containing a red larva. Ch. aromaticum, bulbosum, temulum: Lasioptera carophila

16a Fruit bladder-like, inflated, ± globular, protruding above the umbel. Containing an orange-red larva. Ch. aromaticum: Kiefferia pericarpiicola

16b Fruit tube-like, swollen. Containing a white-yellow larva. Ch. bulbosum: Unidentified gall midge

Last modified 2.iv.2020